/Engine/Source/Runtime/Engine/Classes/EdGraph/EdGraphSchema.h
Request to drop a variable on a node
the response to rejection or performing the drop
virtual bool RequestVariableDropOnNode ( [UEdGraph](API\Runtime\Engine\EdGraph\UEdGraph) * InGraph, [FProperty](API\Runtime\CoreUObject\UObject\FProperty) * InVariableToDrop, [UEdGraphNode](API\Runtime\Engine\EdGraph\UEdGraphNode) * InNode, const FVector2D & InDropPosition, const FVector2D & InScreenPosition )